Unique features of plasticizer-free soft TPU made with bio-based polyol from 3-methyl-1,5-pentanediol and sebacic acid
by Shun Okura, Kunio Mayahara and Hoan Tran, Kuraray
Thermoplastic polyurethane (TPU) is a multiblock copolymer that consists of a hard segment (HS) with short diols and diisocyanates and a soft segment (SS) with polyols and di-isocyanates. Each segment has a microphase separation structure, and properties can be tailored based on formulation and raw material selection. Elasticity is exhibited by the hard segments forming physical crosslinks through hydrogen bonding, and hardness can be adjusted by controlling HS content.
Due to the versatile design possibilities, TPU is used in many applications, such as industrial and medical tubes, smartphone cases, shoe soles and paint protection films. The 3-methyl-1,5-pentanediol (MPD) chemical is an aliphatic diol with a methyl branch at the center position of the main chain, having two equivalent primary hydroxyl groups. The methyl branch provides MPD with many distinctive properties, such as remaining liquid even at low temperature, low viscosity and good transparency.